Data fusion is a useful statistical method that can be applied to multiple sensors or array sensors in many fields. The pH value is a very important parameter in clinical diagnosis, industrial wastewater treatment using a hydrogen ion selective electrode or pH meter. In this study, the examined data fusion methods consist of the arithmetic average and weighted data fusion coefficients used to process the measured pH data. A ruthenium dioxide (RuO2) pH electrode was prepared. RuO2 thin films were deposited onto silicon substrate using a sputtering system. Eight RuO2 hydrogen ion selective electrodes were used to form pH array sensors. From the measurement process, we can simultaneously obtain eight data sets. The experimental results, using the data fusion weighted coefficients obtained a good measurement result even when an individual sensor failed within the array sensors.